Magnetic apparatus for removing tramp iron



Oct. 5, 1943. c. A. RIETZ MAGNETIC APPARATUS FOR REMOVING TRAMP IRON Filed Aug. 2, 1940 2 Sheets-Sheet l i F 'IlEl E h v n w N/ R .0 [MW A Q [a Oct. 5, 1943. c. A. RIETZ 2,330,995 v MAGNETIC APPARATUS FOR REMOVING TRAMP IRON I Filed Aug. 2, 1940 2 Sheets-Sheet 2 FIE L 1 INVENTOR 1 ATTORNLV Patented a. 5, 19 43 MAGNETIC A PAR [F R REMOVING TRAMP ON I Carl ameta san Francisco, Calif; antenna 2, Missal 8 45 1 --1 -c1aim. (01. 209-223) V This inventi n, elates een tallyto appara u for the purpose. f; remov soeca e .tramp r n tmm io swe mat r alsa v In man nstancesas for amp ein the c nmine n ust and in vario s rui pr s n pl nt stray fra me tso i on. o .sol ed t m nunifinds it wa in o the mate ial ben ro sse In th pastit has b ennattempte o rem v uc tr m i on an u e of, s tt ement t aps in t ra l r onve i on it l under 9r trew con e o sut i a vb e l. ou d tha 1. 91 x ed eetsdo n t ins re ctxmn eteremova I Maen t e devi vha e notheen u ili ed, fQ tth s pose, p e Qmab ypea Se, 1 i uch ma net c deviceshave been vailable which have been fragments of iron to be carried along'with the stream of material, andihestream c tmaterial maybefdfasubstantial depth. practical form of apparatus making use of time netic device, which will effectively and positively remove. tramp iron from wet materials. I

Another" object of the invention is to provide a magnetic device for the above purpose which will beabsolutely liquids tight, and which therefore i e subi s ed to Wet m e i l it out anee of deterioration or interruption of service.

Additional objects of the invention will appear from theiollovving deseriptlonin which the preferred embodiment of thelinvention has been set forth in detail in conjunction With the accom panying drawings. i i :Referring toithe drawings-2 Figure 1 is 'a side elevational-viewillustrating a magnetic device incorporating the present in- Figure 2-is an end viewof the device shown in Figure 1, with certain parts beingbroken away andin-cross section; 5? l Figure 3- is an enlarged detail-illustrating the manner in'--w-hichterminals from the magnet-ic It nan object of theinventionfto provide a legs l2 have, thickened medial portions where i 'flow;

Figure 5 is a cross sectional detail taken along win i gare connected to the current supply conductorsy t i ur 4 i a s d e va qna i o apparat ak g s 9 t ma net c de ce o i u es land 2 for removing tramp iron from a liquid the line 55 of Figure 4;

- Fi r 6 s c ec ip eld taili ust a e apparatus where the wet -rn aterial,-is being con exe b m nsg afeed sc 1 Figure 7 is a side elevatiqnal vievv/partlyin cross section, illustrating apparatus incorporating treated; and c Figure t} is a curve illustrating the typeof mag netic field produced bymy nagntic device. a

" Referringfirs't to Figures lie 3 inclusive, the

magnetic devic illustrated comprises awihding lflQadapted to be connected tola suitableesource of direct current..QThis"winding surrounds a magnetic core. I I, the ends of which engage the magnetic legs 12. This assembly is held together by the studs [3 which'are threaded into the fcore; The magnetic ,pole pieces M are formed integrally with theside legs 12, and these Pole pieceshave'coplanar flat surfaces [6,iorrning' Virtually a flat table for the device] Adjacentparallel edge portions I! of the'pole pieces 14 are" shown separated by the strip l8 of resilient rubber. A plate I5 of non-magnetic material is attached to the underside of "the pole pieces, and aids in retaining the rubber strip X8 in, proper position.

' The construction ,and' proportioning of the I parts of the magnetic device are such as to afford a relatively intense magnetic field; with the magnetic flux being concentrated in the vicinityoi the magnetic gap between the pole portions 1 Hi Toattain this object, it will be noted that the side they engage the ends of the core ,I I. 'Arrange men't ofthe pole pieces 14 in a common-plane With a'relatively narrow magnetic gap minimizes ,of the flux flux leakage, and concentrates all between the pole portions II.

It is important that the magnetic device he i I immune to contact with moisture" In .order to posed faces of the magnetic legs 12 are'provided with annular recesses 2!)"t0 accommodate the end edgesof lthe shell I94 In assembling'the devica insn e au dflr-i rl o o -thexmate albe the shell l8'is first assembled with respect to one of the side legs l2, with the open end of the shell uppermost. With the winding l within the shell, the shell is filled with a suitable hot molten bitumastic sealing compound which will solidify at normal room temperatures. The other magnetic leg is then applied and the remaining stud I3 screwed down. The amount of bitumastic sealing compound is such-that as the parts are being thrust tofinal position, all air within the shell l9- and surrounding the winding I0 is expelled, and a small amount of the bitumastic is extruded through the recesses 20. Thus the interior of the device is absolutely sealedagainst penetration of moisture, even though the device may be immersed in liquid.

A waterproof connection to the winding l0 can be made as shown in Figure 3. "In this case a small outlet box 2| is formed integral with one side leg l2, and is normally sealed by cover 22. Terminal wires 23 from the winding I0 extend through opening 24 in the side leg, and'are attached tothe terminal block 25. A flexible rub ber covered conductor cord 26 extends into the box 2|, through sleeve 21, and has its conductors connected to the block 25. Leakage between sleeve-21. and thecord 26 is prevented by the packing gland 2B.

Figures 4 and illustrate apparatus making use of the magnetic device of Figures 1 to 3 inclusive, where it is desiredto remove tramp iron from a flow of liquid material occurring through pipes or conduits. In this case a casing 29 of nonmagnetic material has an inlet connected to the pipe 3|, and an outlet connected to pipe 32.

' The interior of the casing affords apassage for flow of material between the pipes 3| and 32;and

this passage includes an inlet portion 33a, an

. flange 34, is directly exposed to the flow of material through the casing 29. Within the intermediate passage portion 33b, there is a hinged gate 31, the position of which can beadjusted by means of screw 38. Material is forced to pass below the free edge of gate 31, or in other words through the restricted orifice formed between the free end of the gate and the adjacent flat surface of the magnetic device 33. Thus the thickness of the stream of material being subjected to the magnetic action can be adjusted as desired, depending upon theviscosity' or fluidity of the material, i J

In the outlet" portion ',33c of the passage through'casing 29', a 'trapspace 39 is formed below the level of pipe 32, in which tramp iron may 'be 'retained by magnetic 'attractionand settlement. A deflector 4] extends generally over the trap space 39 in order to prevent carrying material into the outlet pipe 32 by relative rapid fluid flow. Material can be removed from space 39 byremoving the end closure 42 The apparatus described above in connection with Figures 4 and 5 will effectively remove all tramp iron from various liquid materials or pulps, even though the flow rates may be relatively high. Forcing the material to pass beneath the gate 31 spreads the fiow intoa relatively flat stream which passes over the poles of the magnetic device, thus making certain that tramp iron is brought sufliciently close to the pole pieces to insure retention. To clean the apparatus of accumulated tramp iron, it is only necessary to disconnect the closure plate 42, or the magnetic device is removed from the flange 34.

Figure 6 illustrates how the magnetic device of Figures 1 and 2 can be incorporated in apparatus where a wet pulp or paste is being conveyed by means of a feed screw. In this case I have shown a conventional feed screw 43 disposed within an ordinary feed screw casing 44. A portion of the lower side of the casing 44 is cut away to provide the opening 45, and this opening is closed by the magnetic device 36. It will be evident that the flights of the feed screw will cause the material to be passed directly over the pole pieces of the magnetic device 36, so that the material being conveyed will be subjected to the intense magnetic field, and tramp iron will be Separated out and retained upon the pole pieces.

Figure 7 indicates'the apparatus making use of the magneticdevice 36 in-conjunction with an open launder. In this case the bottom fiat wall ll of the launderis provided with an opening 48, and this opening is normally closed by the pole pieces of the magnetic device 36. In this instance the magnetic gap between the pole pieces is arranged at right angles to the flow of material, so that the magnetic field effectively acts upon the full width of theflow stream. Here, again, any fragments of iron or other magnetic material carried by the stream of material are separated out by the magnetic pull and are est in'regions adjacent the magnetic gap between the pole portions 17. The curve of Figure 8 illustrates generally the distribution of magnetic flux above the pole pieces. It will be noted that for-regions adjacent the pole portions H, the magnetic flux is relatively intense, while over the remainder of the pole pieces it is relatively weak. Actually with a magnet constructed as described, and consuming approximately watts direct current, the pull upon the end of a square bar measuring one inch square, and spanning the pole portions I1, is in the neighborhood of from 100 to pounds. For areas displaced about inch'to one side of the magnetic gap, the pull upon the same bar falls to about from 6 to 7 pounds; Such a magnetic device has been found effective for removing trampiron from streams of material of about 2 inches or less in depth. The actual width of the magnetic gap in this particularinstance was about inch, or in other words a minor fraction of the depth'of the stream of material for which the device was suitable. The top surface of the device, including both pole pieces, measure about ten. inches square. .The bulging of the magnetic legs as previously described contributes towards producing the desired intense magnetic field in the vicinity of tions of the legs l2.- This proportioning has the eifect of concentrating. the magnetic flux between the pole portions I1, and minimizing magnetic leakage between other portions of the device. Thus in the previous example approximately 90% of the effectiveness of the magnetic pull of the device was available on the pole pieces i4, and approximately 80% was concentrated in a band about two inches wide, symmetrical with the center of the magnetic gap between the pole portions H.

I claim:

In apparatus for removing tramp iron from wet material, a magnetic device including pole pieces having ends forming a substantially flat surface, a fluid conveying casing enclosing said surface, the faces of said pole pieces interrupting said flat surface to form a gap extending longitudinally of said casing, said casing having inlet and outlet pipes spaced above said surface at either end thereof, an adjustable gate pivotally .mounted within said casing for free swinging movement and overlying said surface, said gate extending transversely with respect to the direction of flow of material to cause a flattened stream of fluid passing through said casing to,

flow across said surface, and a stop adjustably mounted in said casing for, engagement with I the outlet side of said gate.

CARL A. RIETZ. 

